Maximum Energy Product<\/strong> <\/p>\n\n\n\n The first contributing attribute is a magnets maximum energy\nproduct, this is measured in Mega Gauss Oersteds (MGOe). <\/p>\n\n\n\n This is the primary indicator of a magnet\u2019s \u2018strength\u2019 as\nusually the higher the maximum energy product value, the greater the magnetic\nfield generated by the magnet. <\/p>\n\n\n\n To calculate the maximum energy product, take a magnet\u2019s remanence (Br) and multiply it by its coercivity (Hc). <\/p>\n<\/div>\n\n\n\n Remanence<\/strong><\/p>\n\n\n\n The remanence is described as the magnetism that is left in\nthe magnet after the removal of external magnetic force applied to magnetise it,\nthis is measured in Gauss. <\/p>\n\n\n\n When a material has been magnetised, it will have remanence, as the magnetism has previously been induced by an external magnetic field.<\/p>\n\n\n\n The remanence value of a magnet is the flux density held by the magnet whilst in a closed circuit <\/p>\n<\/div>\n<\/div>\n\n\n\n Coercivity<\/strong><\/p>\n\n\n\n The coercivity of a magnet is the energy which is required to reduce the magnetisation of a magnetised object to zero, which had previously been magnetised to the point of saturation. <\/p>\n\n\n\n Essentially, it measures a magnetic materials resistance to demagnetisation\nand is measured in Oersteds. <\/p>\n\n\n\n Each factor can only be measured with a hysteresis graph testing machine which plots a second quadrant hysteresis curve. <\/p>\n\n\n\n Open Circuit Flux Density<\/strong><\/p>\n\n\n\n The intensity of a magnetic field, measured in Gauss or\nTeslas (10,000 Gauss = 1 Tesla), is also a very common measurement of a magnets\nstrength as it is the representation of the density of a magnetic field\nproduced by a magnet, known as flux density.<\/p>\n\n\n\n A magnetic field can be visualised as magnetic lines passing\nthrough a magnet along the direction of magnetism, the field strength relates\nto the density of the lines over a given area and the total number of lines is\nthe magnetic flux density. <\/p>\n\n\n\n The remanence value of a magnet is the flux density held by the magnet whilst in a closed circuit, but after being removed from the testing machine it is no longer in a closed circuit and is in an open circuit. The magnetism will fall instantly to a lower level which will be dependant on the ratio between the surface area and its relative magnetic length. <\/p>\n\n\n\n For example, magnets with small poles and long lengths have a much higher open circuit flux densities in comparison to magnets with large poles and small magnetic lengths. <\/p>\n<\/div>\n\n\n\n .<\/p>\n\n\n\n .<\/p>\n\n\n\n Pull Strength<\/strong><\/p>\n\n\n\n Neodymium magnets are very commonly used, and manufacturers\nand suppliers will provide strength for each of their magnets to show how much\nweight a magnet can hold.<\/p>\n\n\n\n The pull strength is the highest possible holding power of a\nmagnet, measured in kilograms. This is the force required to prise the magnet\nfrom a flat steel surface when they are in direct surface-to-surface to contact.\n <\/p>\n\n\n\n The grade of the metal, surface condition and angle of pull\nwill all have an impact on the pull strength of a magnet. <\/p>\n\n\n\n Pull Gap Curve<\/strong><\/p>\n\n\n\n A pull-gap curve plots the\npulling power of a magnet in direct contact with a thick and flat piece of\nsteel and then through a steadily increasing range of air gaps. All magnets can\nbe tested over a variety of air gaps using a pull-gap testing machine. <\/p>\n<\/div>\n<\/div>\n\n\n\n So, when it comes to selecting a magnet the key things to look out for are the maximum energy product value of a magnet, the open circuit or surface gauss value and the maximum pull strength. These attributes give you the opportunity to compare individual magnets. <\/p>\n\n\n\n![\"\"](\"https:\/\/www.first4magnets.com\/blog\/wp-content\/uploads\/2021\/04\/Image-Graph-1-Strength-700x494.png\")
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